Circuit interrupter



' March 14, 1933. G. A. BURNHAM CIRCUIT INTERRUPTER 2 sheets-sheet 1 Filed Feb. l, 1950 ML @M March 14, 1933. A. BURNHAM 1,901,363

CIRCUIT INTERRUPTER` Filed Feb. l, 1950 2 Sheets-Sheet 2 Patented Mar. 14, 1933 UNITEDk STATES PATENT ori-ica GEonGEA. BUBNHAM, or SAUGUS, MASSACHUSETTS, AsSIGNoR To coNmT ELECTRIGAL MANUFACTURING coaronATroN, or SOUTH BoSToN, MASSACHUSETTS, A ooaro- RATION or MASSACHUSETTS CIRCUIT INTERRUPTER Application led February 1, 1930. Serial No. 425,295.y

This invention' relates to electric switches land circuit interrupters, especially to the o1limmersed type.

One of the objects of the present invention is theprovision of ay switch or interrupter which is so arranged that the circuit interrupting arc is directed against a cold body having goodheat conducting ability so that the arc is caused to be rapidly `cooled and .l0 extinguished; and further arranged so that when the arc has been extinguished andthe switch is open, the space between said arc cooling bodyand the conducting parts .of

the switch are Voccupied by fthickmasses of '15 oil. whereby to provide adequate insulation between the terminals-ofthe switch.

Another object of the invention is to support the aforesaid arc cooling body on'the movable switch member. v In an oil-immersed circuit interrupter, the circuit interrupting-arc is directed magneti# cally, either by the natural shape of the currentpath through the switch or by a specially 1provided current path, toward the side wa l of. the enclosing casing. If the current to be interrupted is severe, the arc may be deflected far enough to come in contact with the side wall' or the insulating lining there` of. Thus, a further object of the invention isto locate the arc cooling body between the wall of the enclosing casing and the arcing members, so that the arc is prevented from impinging directly against the wall.

A further object is to providea plurality Y of closely-spaced heat-absorbing metal plates, which preferably are carried by and are mov vable with the movable switch member, in such relation with the arc which is drawn between the arcing members under the oil that the arc is caused to play against the plates and pass into the spaces therebetween whereby to be cooled and extinguished.

A further Objectis generally toimprove '45 circuit interruptersand circuit interrupting rupter, unnecessary-for the understanding of the present invention, being omitted.

Fig. 2 is a view similar to Fig. 1y vbut with the clrcuit interrupter in open condition.

Fig. 3 is a section taken along line 3--3 ofF1g.2.

, Fig. 4 is a perspective view of one ofthe arc cooling plates of Figs. '1 and 2. F ig. 5 is a plan view of amodifed'construction of `the movable Switch member adapted for association with the stationary switch members of Figs. 1rand Fig.r 6 is a detailed side elevation of the bank of arc cooling plates at one end 'of thel movable Switch member. 1 v' Fig. 7 is a` sectional detail of a-modied arrangement :of arc cooling plates. Fig. 8 is a plan view of Fig. 7. The present invention is applied to the circuit interrupter described and claimed inthe copending application of'Chester DQAins- Worthy; Serial No. 242,666, led December 27, 1927, now Patent No.1,762,604, dated June 10, 1930, and assigned to the assignee of the present application.

The interrupter includes the insulated stationary switch members 10 having conducting studs 12 to vthelower ends of whichthe inverted laminated or brush members Mare secured. Auxiliary Contact or arcingmemvbers 16 in the form of cylinders are located beneath the main contact members 14 and are supported in frames 18 iXedto the studs 12. The movable switch member includes the lifting rod 2O which carries a bridging member 22 at its lower end and which connects and bridges the two brush members and thereby carries the current through the switch when the switch is closed. The stationary varcing' members 16 are engaged by similar movable arcing members 24. Said movable arcing members are secured to the outer ends of conducting arms 26 the inner ends of which are pivotally secured to or are fulcrumed on the upturned inner ends 28 of conducting and supporting members having sections 30 which are disposed below said arms 2,6-and other sections 32 which are disposed'above said arms thereby forming, in elect, current' conducting loops which set up magnetic fields 1 that react on the magnetic iields surrounding the current carrying arms 26 in a direction which urges said arms, and-the arcing inembers carried thereby, upwardlyor into forcible engagement with the stationary arcing members 16. The magnetic iux setup by said loops also traverses the arc Zones between said separable arcing members in a direction which is angularly related to tlief the* separable arcingmembers. ,Normally the oil in which thefswitch members are immersed .occupies the space betweenthe side wall andthe separable switch members altliough,-when the switch opens under heavy current, the oil may be displaced and the space occupied by thegases resulting vfrom the circuit interrupting` arc. Y Y Y f In vaccordance with the present invention, means are provided against whichfthev cirf cuit interrupting arc is brought in contact whereby to cool the arcs and effect their rapid .extinguishment Also in accordance with the `present invention, the ysaid arci-cooling means are located betweenv the separate arcing'members and the lside wallof the enclosing casing whereby to preventthe varc `from coming directly into Contact with the side wall and also to cool' the gases down to such a temperature that they cannot damage the side Wall' and haveno material conductivityA when and if they ultimately do contact vwith the side wall in rising tothe top of the Casing.. v

f- In the constructionillustrated in Figs. l

through 4, the arc cooling means consists of relatively thick and, massive plates 42 which are composed of afmetal as copper thathas good` heat; absorbing Vability and'which are located YsutlicientlyA close to the separable` arcing members so thattlie arcs are brought magnetically into heat-dissipating engagement therewith. Said vplates lare vertically disposed beside said arcingmembers and extend on opposite sides therebeyond for a sulicient`- distance to occupy the entire transverse width of thev Zone. Saidplates, at the bottom,are provided with inturned lugs i3 which are secured by screws 44 to insulating bars 46 which extend beneath the arcingimembers and are secured by bolts i8 tothe legs 36 oi theirame Y the arc cooling plates 58 are generally-hori- 'zontally extended in verticallyv spaced rela- 34;. The plates 4:2 are spaced a suiicient distance from the conducting paths'o the stationaryfswitch members so that the oil therebetween provides-*adequate insulation therebetween both when the switch is closed and when the switch is opened and the circuit interrupting arcs have been extinguished. The plates are high enough so that when the switch yopens there is a suliicient vertical extent oi the plates presented to the action of the arcs so that the arcs are cooled and quenched by the time 'the' switch -is-completelyf` opened. rlhe arrangement also is such 4that when the switch opens vthe oil in which the'parts are immersed will not be deflected away from the plates and the movable arcing members but can flow reelytherebetween and thus provide maximum insulation" therebetween. With this arrangement, the magnetic field provided bythe loopsfiorces the arcs outwardly and into engagement with the arc, cooling plates '42 so vthat the arcs are .causedlto becomerapidly cold and extinguished. Said plates are interposed between the arcing members and the sidewalls of the'casing and so prevent the arcs from coming into contact with they sidev wall and function to cool the arc gases sulliciently to render themY harmless if they should t come into contact with the side .walls as; the

gases pass upwardly through the oil.

In lthe vconstruction illustrated -in Figs. 5 and 6, a m'odied 'arrangement is provided.

A plurality jof arc-cooling and heat-conducting pates 50 are located adjacent the arcing Vmembers andare vertically arranged in parallel spaced relation and present. their inner narrow edges to tlie arcsrf- Said plates are .thisend, are supported in spaced relation on insulating tubes 52 and are securedtogether .between the end plates 54 by bolts 56 which pass through said tubes and said end plates.

Said end plates are secured to the ends of the 'l aiforesaid insulating bars-46. The spaces between the plates are relatively narrow, say,

Yapproximately tliethiclness ofia pfate, and are freely open at all sides sortliat oil and ring engagement with the broad facesof the yplates thereby to cool the arcs rapidly. The

arc gases that emerge from between theplates at the outer edges thereof remote frointhe arcing members are cool and so cannotl cause trouble when andnif they engage the insulating lining l0 orv the metal side wall 38 of the enclosing casing. For somepurposes, it may be advantageous to yhave said plates 50 conn `nected electrically vtogetherV in whichevent the plates can be mounted directly upon the tous 5a 'Y i f In the modification shown 'in Figs. 7 and 8,

tion and are also' inclined upwardly `and out- 'preferably insulated ,from eachother and, tol-100 ported by preferably insulating plates 60 the lower ends of which are attached to the insulating bars 4G. vWith this arrangement, as

f before, the circuit interrupting arc is vblown against the frontedges of the plates and into the spaces betweenthe plates and thus is caused to cool and become extinguished. The plates, being upwardly inclined, di-

f rect the cool arc gases upwardly so that they are not so liable to come in contact with the side wall of the enclosing casing. v

In the modifications shown in bothy Figs. 5 and 7 the plates are arranged to be materially beneath and away from the live parts of the stationary switch members, as with they modification shown in F ig. l, so as to provide good insulation between the terminals of thek switch. when the' switch is open. n

In all of the modiiications, the arc cooling plates are normally insulated from the switch circuit and from ground at least to such a degree that no material amount of current can flow from the plates either to ground or to the switch circuit external of the arc when the circuit interruptingarc is in contact with the plates. The arc cooling plates, being carried by the movableswitch member, are moved downwardly through the cool oil upon switch opening movement and thus are kept cool at the time they are active in cooling the arc gases.

The oil in which the switch members are immersed can be replaced with any other suitable insulating medium if desired.

The structure can be otherwise modified without departing from the spirit of the invention.

I claim:

1. A circuit interrupter having the combination of an oil containing enclosing casing, separable arcing members immersed in the oil in said casing, andan insulated metal plate immersed in the oil between the wall of said casing and said arcing members and located in a plane parallel with the line of separation of said contact members and in position to intercept the circuit interrupting arc drawn between said contact members and prevent it from engaging said wall, said plate also having good heat-absorbing ability and adapted to cool the circuit interrupting arc.

2. A circuit interrupter having thecombination. of an oil containing enclosing casing,

. separable arcing members immersed in the oil in said casing, and an insulated metal plate immersed in the oil between the wall of said casing and said arcing members and located in a plane parallel with the line of separation and at one side of said contact members and in position to intercept the circuit interrupting arc drawn therebetween and prevent it from engaging said wall, said plate also having good heat-absorbing vability and adapted tocool the circuit interrupting arc, and means to direct the circuit interrupting arc to lie against said plate along the length thereof.

- 3. A circuit interrupter having the combi-- nation of an oil containing enclosing casing, separable arcing members immersed in the oil in said casing, and a. continuous heat-absorbing arc-cooling body located between said arcing members in a plane parallel with the Y line of separation of the contact members and between said contact members and the wall of said casing and adapted to intercept the circuit interrupting arc drawn therebetween and cool it.

cooling body located alongside and between v 7 4. A circuit interrupter havin vthe com-` said arcing members and the wall of said cas- Ling and disposed in a plane parallel withV the line of separation of the contact members and adapted to intercept the circuit interrupting arc and cool it, and means to directthe circuit interrupting arc to lie against said arccooling body'along the length thereof.

5. An electric oil/switch having a stationary switch member including stationary arcingvmembers, a movable switch member including a movable arcing member, and a heati absorbing arc-cooling body carried by and movable with said movable switch .member and disposed alongside and in position to be engaged by the circuit interrupting arc drawn between said arcing members when the switch i opens under load, said body being moved through the oil by said movable switch member when the switch opens.

6. An electric switch having a stationary switch memberincluding an arcing member, a movable switchmemberincludingan arc- -ing member, means providingabody of oil in which the arc is drawn, and a heat-absorbing `arc-cooling body insulated'from said arcing y members and carried by and movable with said movable switch member and disposed adjacent and in a plane parallel with the line of separation of said arcing members in position to be engaged'by and to cool the circuit Y interrupting arc along its length.

7. Ain electric switch having a stationary switch member including anarcing member, a movable switch member including an arcing member, a lheat-absorbing arc-cooling v body insulated from saidarcing members and carried byand movable with said movable switchmember and disposed alongside and in a plane parallel with the line otseparation of said arcing members in position to be i Vengaged by and to cool the circuit interrupting arc drawn therebetween, and means to maintain an insulating liquid between said body and said arcing members when the switch is open.

'along its length, and means to direct. the ciricuit interrupting arc to lie against said body along its length; Y f

9. An electric Aswitch yhaving stationary and movable ar'cing members,a heat-absorbing arc-cooling body carried by` and movable'with the movable arcing member and disposed in a plane parallel with and in position to be engaged by and to cool the circuit interruptingv arc between said arcing meinbers and'which constitutes a barrier to the lateral expansian of said arc, and magnetic means to directthe circuitV interrupting arc Aagainst and into intimate Contact with said 'body throughout its length.

10. Anl electric switch khaving stationary and movable arcing members, a stack of heatabsorbing arc-cooling plates carried-by and movablel with the movable aicing member 'and Vdisposed in position to presentA their edgesto the circuit interrupting arc between said arcing members," andy magnetic means karranged to direct the circuit interrupting 'are against said stack.

11..A circuit interrupter including an oil containing enclosing casing, separable arcing members immersed `in the oil therein, and a 'plurality of closely-spaced heat-absorbing .and arc-cooling Vplates which are insulated l from the interrupter circuit and are disposed which the arc gases canbe located, and means independent of any action of the` arc gases tro circulate a cooling iiuid body in the spaces between said plates at the time the arc exists, comprising means to move said plates, in the direction of their lengths through ai cool fluid body during the separation of saidi arcing members. In testimony whereof, I have signed m name to this specification,

esoneri A. BURNHAM.

adjacent the separable arcing members in Y planes parallel with the line of separation of said arcing members and in position to be engaged by the circuit interrupting are and to f cool the arc, each of said plates presenting a 1 continuous heat-absorbing surface alongside the arc which is adapted to' abstract heat from the arc throughout its length.y

12. A circuit interrupter having separable arcing members, an arc cooling plate disposed in position to be acted on and to cool the arc e gases of an are drawnbetween said arcing members, and means to move said plate through a liquid body so as to move the liquid over the gas-engaging surface of said plate at the time it is engaged by the arc gases.

13.7 A circuit interrupter includingseparable arcing members, an arc cooling device including spaced arc cooling plates vbetween 'which the arc gases can be located, andmeans independent of any action of the arc gases to circulatev a cooling fluid body in the spacesk between said platesat the time thearc exists.

14. A circuit interrupter Vincluding sepay rable arcing members, anarc cooling device including spaced arc cooling plates between iio 

